U.S. patent application number 12/745861 was filed with the patent office on 2011-03-10 for lubricating composition for a four-stroke engine with low ash content.
This patent application is currently assigned to Total Raffinage Marketing. Invention is credited to Jerome Obiols, Ludivine Pidol, Isabelle Rogues De Fursac, Jean-Marc Savoie.
Application Number | 20110059877 12/745861 |
Document ID | / |
Family ID | 39561733 |
Filed Date | 2011-03-10 |
United States Patent
Application |
20110059877 |
Kind Code |
A1 |
Obiols; Jerome ; et
al. |
March 10, 2011 |
LUBRICATING COMPOSITION FOR A FOUR-STROKE ENGINE WITH LOW ASH
CONTENT
Abstract
The present disclosure relates to a lubricating composition for
a four-stroke engine, with low ash content including: a) one or
more base oils selected from oils of Groups I-IV, preferentially
from oils of Group III or IV from the API classification, b) at
least one compound (b) selected from the group of heavy PAOs with a
kinematic viscosity at 100.degree. C. comprised between 75 and
3,000 cSt, optionally mixed with one or more compounds selected
from the group of polymeric compounds of the polyisobutene (PIB)
type, or one of their mixtures, and c) at least one ester of
formula R(OH).sub.m (COOR'(OH).sub.p).sub.n wherein m is an integer
from 0 to 8, preferably from 1 to 4, n is an integer from 1 to 8,
preferably from 1 to 4 and p is an integer from 0 to 8, preferably
from 1 to 4 and wherein the sum p+m is strictly greater than zero,
R and R' represent independently of each other a saturated or
unsaturated, linear or branched hydrocarbon group, optionally
substituted with one or more aromatic groups and including from 1
to 30 carbon atoms, and borated derivatives thereof; the
composition having a sulfated ash content less than or equal to
0.5%, as measured according to the ASTM D874 standard, a phosphorus
content less than or equal to 500 ppm, as measured according to the
ASTM D5185 standard, and a sulfur content less than 0.2%, as
measured according to the ASTM D5185 standard. The composition has
good detergency properties, the use of which promotes fuel
savings.
Inventors: |
Obiols; Jerome; (Lyon,
FR) ; Pidol; Ludivine; (Cachan, FR) ; Savoie;
Jean-Marc; (Ternay, FR) ; Rogues De Fursac;
Isabelle; (Lyon, FR) |
Assignee: |
Total Raffinage Marketing
|
Family ID: |
39561733 |
Appl. No.: |
12/745861 |
Filed: |
December 2, 2008 |
PCT Filed: |
December 2, 2008 |
PCT NO: |
PCT/FR08/01668 |
371 Date: |
November 19, 2010 |
Current U.S.
Class: |
508/186 ;
508/370; 508/507; 508/519 |
Current CPC
Class: |
C10M 2207/289 20130101;
C10M 2215/064 20130101; C10M 169/044 20130101; C10M 2203/1025
20130101; C10M 2223/043 20130101; C10N 2030/04 20130101; C10N
2030/43 20200501; C10N 2030/06 20130101; C10M 2205/026 20130101;
C10N 2010/04 20130101; C10N 2030/42 20200501; C10N 2040/25
20130101; C10M 161/00 20130101; C10M 2205/028 20130101; C10M
2207/026 20130101; C10M 2223/045 20130101; C10N 2030/54 20200501;
C10N 2030/45 20200501; C10M 2205/0285 20130101; C10M 2203/1025
20130101; C10N 2020/02 20130101; C10M 2205/028 20130101; C10N
2020/02 20130101; C10M 2203/1025 20130101; C10N 2020/02 20130101;
C10M 2205/028 20130101; C10N 2020/02 20130101 |
Class at
Publication: |
508/186 ;
508/519; 508/370; 508/507 |
International
Class: |
C10M 129/74 20060101
C10M129/74; C10M 137/10 20060101 C10M137/10; C10M 145/14 20060101
C10M145/14 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 3, 2007 |
FR |
0708423 |
Claims
1. A lubricating composition with low ash content for four-stroke
engines comprising: a) one or more base oils selected from the oils
of Groups I-V, preferentially from oils of Group III or IV from the
API classification; b) at least one compound (b) selected from the
group of heavy PAOs with a kinematic viscosity at 100.degree. C.
comprised between 75 and 3,000 cSt, in an optional mixture with one
or more compounds selected from the group of polymeric compounds of
the polyisobutene (PIB) type; and c) at least one ester of formula
R(OH).sub.m (COOR'(OH).sub.p).sub.n wherein m is an integer from 0
to 8, n is an integer from 1 to 8, and p is an integer from 0 to 8,
and wherein the sum p+m is strictly greater than zero, R and R'
represent independently of each other a saturated or unsaturated,
linear or branched hydrocarbon group, optionally substituted with
one or more aromatic groups, and including from 1 to 30 carbon
atoms, and borated derivatives thereof; the composition having a
sulfated ash content less than or equal to 0.5%, as measured
according to the ASTM D874 standard, a phosphorus content less than
or equal to 500 ppm as measured according to the ASTM D5185
standard, and a sulfur content less than 0.2% as measured according
to the ASTM D5185 standard.
2. The composition according to claim 1 wherein the ester (c)
contains at least one free hydroxyl OH group belonging to the group
R, the OH group being located in the alpha, beta or gamma position
with respect to the carbon of the CO function of an ester function
on which the group R is bound, and/or contains at least one free
hydroxyl OH group belonging to the group R', said OH group being
located in the beta, gamma or delta position with respect to the
oxygen of the COO group of an ester function on which the group R'
is bound.
3. The composition according to claim 1, wherein the group R' of
the ester (c) represents a C.sub.1-C.sub.10 group.
4. The composition according to claim 3, wherein p is strictly
greater than zero and the group R of the ester (c) represents a
C.sub.8-C.sub.25 group.
5. The composition according to claim 4, wherein at least one ester
(c) is selected from glycerol monoesters or diesters,
preferentially selected from glycerol mono-oleate, glycerol
stearate or isostearate and borated derivatives thereof.
6. The composition according to claim 3, wherein n is an integer
comprised between 1 and 4 and the R group of the ester (c)
represents a C.sub.1-C.sub.5 group.
7. The composition according to claim 6, wherein at least one ester
(c) is selected from citrates, tartrates, malates, lactates,
mandelates, glycolates, hydroxypropionates, hydroxyglutarates or
borated derivatives thereof.
8. The composition according to claim 1, leading to minimum fuel
savings as measured on a M111FE test, of at least 2.5% and meeting
the ACEA-C1 specifications defined by the European Automobile
Manufacturers' Association.
9. The composition according to claim 1, having a kinematic
viscosity at 100.degree. C., as measured by the ASTM D445 standard,
comprised between 5.6 and 16.3 cSt.
10. The composition according to claim 1, with a 5W30 grade
according to the SAEJ300 classification.
11. The composition according to claim 1, with a viscosity index VI
larger than or equal to 130.
12. The composition according to claim 1, wherein the base oil or
the mixture of base oils (a) amounts to at least 70% by weight of
the composition.
13. The composition according to claim 1, wherein the base oil or
the mixture of base oils (a) comprises: at least 60% by weight,
based on the total lubricant weight, of one or more base oils of
Group III; and at least 10% by weight, based on the total lubricant
weight, of one or more base oils of Group IV.
14. The composition according to claim 1, comprising a compound (b)
selected from the group of heavy PAOs, and a compound (b) selected
from the group of polymeric compounds of the FIB type.
15. The composition according to claim 1, comprising 0.1 to 6% of
at least one compound (b) and from 0.1 to 2.5% of at least one
compound (c).
16. The composition according to claim 1, comprising at least one
anti-wear compound of the zinc dithiophosphate type, optionally
combined with an amine phosphate.
17. The composition according to claim 1, comprising at least one
anti-wear compound of the zinc dithiophosphate type in an amount
less than or equal to 1%.
18. The composition according to claim 1, free of any amine
phosphate type additive.
19. The composition according to claim 1, free of any molybdenum
friction modifier additive.
20. The composition according to claim 1, comprising at least one
antioxidant compound, preferably ashless, preferentially of the
phenolic or aminated type.
21. The composition according to claim 1, comprising from 0.01 to
5% of one or more antioxidant additives.
22. The composition according to claim 1, with a BN, determined
according to the ASTM D-2896 standard, less than or equal to 8
milligrams of potash per gram of lubricant.
23. The composition according to claim 1, comprising between 0 and
3% of a VI-enhancing polymer selected from polymeric esters, olefin
copolymers (OCP), homopolymers or copolymers of styrene, butadiene
or isoprene, polymethacrylates (PMAs).
24. A method for making a lubricating composition according to
claim 1, by diluting a package of additives comprising at least one
compound (b) and at least one compound (c), in a base oil or a
mixture of oil bases (a) and wherein a VI-enhancing polymer is
optionally added.
25. The making method according to claim 24, wherein the additive
package is diluted so as to amount to 10-30% by weight of the
lubricating composition, and wherein the VI-enhancing polymer
amounts to 0-3% by weight of the lubricating composition.
26. A package of additives for a four-stroke engine lubricant with
a sulfated ash content less than or equal to 0.5%, as measured
according to the ASTM D874 standard, a phosphorus content less than
or equal to 500 ppm, as measured according to ASTM D5185, and a
sulfur content less than 0.2%, as measured according to the ASTM
D5185 standard, the package comprising: at least one compound (b),
a heavy PAO optionally mixed with a PIB; at least one hydroxylated
ester (c); and optionally anti-wear and extreme pressure additives,
friction modifiers, detergents, antioxidants, detergents either
overbased or not, flow point lowering additives, dispersants,
anti-foam additives, thickeners, polymers enhancing the viscosity
index.
27. The additive package according to claim 26 comprising: 0.5-30%
by weight of at least one compound (b), a heavy PAO optionally
mixed with PIB; and 0.5-15% by weight of at least one hydroxylated
ester (c).
28. The use of a composition according to claim 1, as a lubricant
for a four-stroke engine.
29. The use of at least one ester of formula R(OH).sub.m
(COOR'(OH).sub.p).sub.n wherein m is an integer from 0 to 8, n is
an integer from 1 to 8, and p is an integer from 0 to 8, and
wherein the sum p+m is strictly greater than zero, R and R'
represent independently of each other a saturated or unsaturated
linear or branched hydrocarbon group, optionally substituted with
one or more aromatic groups, and including 1 to 30 carbon atoms,
and borated derivatives thereof, as a friction modifying agent for
the preparation of a lubricating composition for a four-stroke
engine with a sulfated ash content less than or equal to 0.5%, as
measured according to the ASTM D874 standard, a phosphorus content
less than or equal to 500 ppm, as measured according to ASTM D5185,
and a sulfur content less than or equal to 0.2%, as measured
according to the ASTM D5185 standard.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a National Stage Entry of International
Application No. PCT/FR2008/001668, filed on Dec. 2, 2008, which
claims priority to French Application 07 08 423, filed on Dec. 3,
2007, both of which are incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The present invention relates to a lubricating composition
for a four-stroke engine with low ash content, having good
detergency properties, the use of which promotes fuel savings, and
comprising at least one hydroxylated or derived ester.
TECHNOLOGICAL BACKGROUND
[0003] Because of environmental concerns, it is increasingly sought
to reduce polluting emissions and to achieve fuel savings in
vehicles. The nature of the engine lubricant has an influence of
both of these phenomena. On the one hand, the behavior of the
lubricant in reducing friction will have an impact on fuel
consumption. This is mainly the quality of lubricating bases,
either alone or combined with polymers enhancing the viscosity
index and with friction-modifying additives, which give to the
lubricant its "fuel eco" properties.
[0004] On the other hand, because of the dilution of the fuel by a
portion of the engine lubricant, certain components of the
lubricants will be found after combustion in the exhausted gases of
the vehicles. These components, in particular certain additives,
may generate sulfur, phosphorus, sulfated ashes which will damage
the post-treatment systems installed in vehicles. The ashes are
detrimental for particle filters and phosphorus acts as a poison
for catalytic systems.
[0005] In engine applications, it will therefore be sought to
accordingly adapt the formulations of lubricants, whether this be
in the selection of lubricant bases or additives. For automobile
engines, the use of lubricants specifically formulated in
observance of certain specifications, in particular the low ash
content (so-called "low saps") ACEA-C4 or (so-called "low saps" and
"fuel eco") ACEA-C1 specifications, elaborated by the European
Automobile Manufacturers' Association, is preferred. These
specifications impose to the lubricants limiting contents of
sulfated ashes (generated by the presence of metals), sulfur and
phosphorus, whence the designation "low saps" for "Sulfated Ashes,
Phosphorus, Sulfur".
[0006] Lowering the level of ashes, sulfur and phosphorus in engine
lubricants while maintaining high levels of required performances
is a challenge because these elements are present in the most
currently used base oils and additives. Thus, for example,
detergent additives, preventing the formation of deposits at the
surfaces of metal parts by dissolution of secondary oxidation and
combustion products, and which are key compounds of a formulation
of an engine oil, contain metal salts which generate ashes. These
are generally sulfonates, phenates, salicylates of earth alkaline
metals such as calcium, magnesium, either overbased or not.
[0007] In order to be able to lower the detergent contents of the
lubricants with the purpose of reducing its ash content, while
maintaining adequate cleaning of the engine parts, it is necessary
to act on the capacity of other compounds of the lubricant of
forming a minimum of deposits. A possible route for obtaining low
ash content lubricants, retaining good detergency behavior in spite
of reduced detergent content, and having good fuel eco properties,
is to prefer the use of certain unconventional mineral base oils or
synthetic bases. These bases have the advantage of better
temperature resistance and better resistance to oxidation as
compared with conventional bases, which minimizes the formation of
deposits. The treatment level of lubricants with detergent may
thereby be lowered and the ash content lowered.
[0008] Their naturally high viscosity index (VI) leads to
lubricants having good fuel eco properties, and the amount of
polymers enhancing VI, generating deposits in the lubricants, may
thereby be limited. Moreover, the sulfur content of unconventional
mineral bases is comparatively lower than that of standard mineral
bases because they undergo extensive hydrotreatments, and synthetic
bases are sulfur-free, which facilitates observance of the limiting
sulfur contents imposed by the ACEA specifications. By
"unconventional mineral bases" are meant the bases of Group III
according to the classification of the American Petroleum Institute
(API), having a high viscosity index VI (typically above 130),
commonly designated as "Group III+ bases", or else the bases
derived from GTL (Gas to Liquid) processes.
[0009] So-called Group III+ unconventional mineral bases are
prepared in order to improve their cold properties, to decrease
their volatility and increase their viscosity index VI), in order
to reach values above 130. These are hydro-isomerized bases, which
may be prepared from residues stemming from a hydrocracking
treatment, possibly added with waxes or Gatsch petrolatum, and
submitted to extensive catalytic deparaffinization. In the
following description, and in the absence of any specification, the
term "Group III bases" designates any type of mineral base of Group
III according to the API classification, whereas the term
"unconventional Group III base" or "Group III base" designates the
Group III bases with VI above 130.
[0010] The synthetic bases are for example polyalphaolefins (PAOs),
esters, and poly internal olefins (Group IV, V and VI,
respectively, according to the API classification). In spite of
their advantages, the aforementioned bases require a certain number
of complex refining operations for the III+ Groups and of synthesis
for Groups IV and V, which has an influence on their price and on
their availability. The present invention relates to low saps and
fuel eco lubricating compositions for a four-stroke engine,
comprising an additivation system allowing the use of an increased
number of lubricating bases, notably including conventional Group
III bases.
SUMMARY
[0011] The object of the present invention is lubricating
compositions for a four-stroke engine, containing additives
providing per se a minimum of ashes, sulfur and phosphorus, totally
or partly replacing standard additives used in this type of
application, which in combination with each other, allow said
lubricating compositions to retain their optimum detergency and
fuel eco properties with low or very low content of ashes, sulfur,
phosphorus. When one speaks here of "retaining" or "enhancing" the
detergency properties of a lubricant, this notably means, at
constant detergent content, the minimization of formation of
deposits by the different components of the lubricant, notably high
temperature deposits.
[0012] The compositions according to the invention are lubricating
compositions for a four-stroke engine comprising:
[0013] a) one or more base oils selected from Group I-V oils,
preferentially from Group III or IV oils, from the API
classification.
[0014] b) at least one compound (b) selected from the group of
heavy PAOs, with a kinematic viscosity at 100.degree. C. comprised
between 75 and 3,000 cSt; in an optional mixture with one or more
compounds selected from the group of polymeric compounds of the
polyisobutene (PIB) type, or one of their mixtures, and
[0015] c) at least one ester of formula R(OH).sub.m
(COOR'(OH).sub.p).sub.n wherein m is an integer from 0 to 8,
preferably from 1 to 4, n is an integer from 1 to 8, preferably
from 1 to 4, and p is an integer from 0 to 8, preferably from 1 to
4 and wherein the sum p+m is strictly greater than zero, R and R'
represent independently of each other a saturated or unsaturated,
linear or branched, hydrocarbon group, optionally substituted with
one or more aromatic groups and including from 1 to 30 carbon
atoms, and its borated derivatives;
[0016] said composition having a sulfated ash content of less than
or equal to 0.5%, as measured according to the ASTM D874 standard,
a phosphorus content less than or equal to 500 ppm as measured
according to the ASTM D5185 standard, and a sulfur content less
than 0.2% as measured according to the ASTM D5185 standard.
[0017] According to a preferred embodiment, the ester (c) contains
at least one free hydroxyl OH group belonging to the R group, said
OH group being located in the alpha, beta or gamma position with
respect to the carbon of the CO function of an ester function on
which the group R is bound, and/or contains at least one free
hydroxyl OH group belonging to the group R', said OH group being
located in the beta, gamma or delta position, with respect to the
oxygen of the COO group of an ester function on which the group R'
is bound. Preferably, the group R' of the ester (c) represents a
C.sub.1-C.sub.10, preferably C.sub.2-C.sub.6 group. According to
one embodiment, p is strictly greater than zero and the group R of
the ester (c) represents a C.sub.8-C.sub.25, preferably
C.sub.12-C.sub.18 group.
[0018] Preferably, at least one ester (c) will be selected from
glycerol monoesters or diesters, preferentially selected from
glycerol mono-oleate, glycerol stearate or isostearate and their
borated derivatives. According to one embodiment, n is an integer
comprised between 1 and 4 and the group R of the ester (c)
represents a C.sub.1-C.sub.5, preferentially C.sub.1-C.sub.3 group.
Preferably, at least one ester (c) is selected from citrates,
tartrates, malates, lactates, mandelates, glycolates,
hydroxypropionates, hydroxyglutarates or their borated
derivatives.
[0019] The composition according to the invention leads to minimum
fuel savings as measured on a M111FE test, of at least 2.5% and
meets the ACEA-C1 specifications defined by the European Automobile
Manufacturers' Association. According to a preferred embodiment,
the composition has a kinematic viscosity at 100.degree. C. as
measured by the ASTM D445 standard comprised between 5.6 and 16.3
cSt, preferentially comprised between 9.3 and 12.5 cSt. According
to a preferred embodiment, the composition has a grade of 5W30
according to the SAEJ300 classification. According to a preferred
embodiment, the composition has a viscosity index VI larger than or
equal to 130, preferentially larger than 150, preferentially larger
than 160.
[0020] According to a preferred embodiment, in the composition, the
base oil or the mixture of base oils (a) amounts to at least 70% by
weight of said composition. According to a preferred embodiment, in
the composition, the base oil or the mixture of base oils (a)
comprises:
[0021] at least 60% by weight, based on the total weight of the
lubricant, of one or more base oils of Group III
[0022] at least 10% by weight, based on the total weight of
lubricant, of one or more base oils of Group IV.
[0023] According to a preferred embodiment, the composition
comprises a compound (b) selected from the group of heavy PAOs, and
a compound (b) selected from the group of polymeric compounds of
the PIB type. According to a preferred embodiment, the composition
comprises from 0.1 to 6%, preferentially from 2 to 4% of at least
one compound (b) and from 0.1 to 2.5%, preferentially from 0.5 to
1.5% of at least one compound (c). According to a preferred
embodiment, the composition comprises at least one anti-wear
compound of the zinc dithiophosphate type, in possible combination
with an amine phosphate. According to a preferred embodiment, the
composition comprises at least one anti-wear compound of the zinc
dithiophosphate type in an amount less than or equal to 1%,
preferentially less than or equal to 0.5%.
[0024] According to a preferred embodiment, the composition is free
of any additive of the amine phosphate type. According to a
preferred embodiment, the composition is free of any molybdenum
friction-modifying additive. According to a preferred embodiment,
the composition comprises at least one antioxidant compound,
preferentially ashless, preferentially of the phenolic or aminated
type. According to a preferred embodiment, the composition
comprises from 0.01 to 5% of one or more antioxidant additives.
[0025] According to a preferred embodiment, the composition has a
BN, determined according to the ASTM D-2896 standard, less than or
equal to 8 milligrams of potash per gram of lubricant,
preferentially less than or equal to 6.5 milligrams of potash per
gram of lubricant. According to a preferred embodiment, the
composition comprises between 0 and 3%, preferably between 0 and
2.5% of a VI-enhancing polymer, selected from polymeric esters,
olefin copolymers (OCPs), homopolymers or copolymers of styrene,
butadiene or isoprene, polymethacrylates (PMAs).
[0026] According to another object, the invention relates to a
method for making a composition according to the invention by
diluting a package of additives comprising at least one compound
(b) and at least one compound (c), in a base oil or a mixture of
base oils (a), and wherein one VI-enhancing polymer is optionally
added. According to a preferred embodiment, the package of
additives is diluted so as to amount to 10-30%, preferentially
15-20% by weight of the lubricating composition and wherein the
VI-enhancing polymer amounts to 0-3% by weight of the lubricating
composition.
[0027] According to another object, the invention relates to a
package of additives for a four-stroke engine lubricant with
sulfated ash content less than or equal to 0.5%, as measured
according to the ASTM D874 standard, a phosphorus content less than
or equal to 500 ppm, as measured according to ASTM D5185, and a
sulphur content less than 0.2% as measured according to the ASTM
D5185 standard, characterized in that it comprises: [0028] at least
one compound (b), a heavy PAO optionally mixed with a PIB; [0029]
at least one hydroxylated ester (c); [0030] optionally, anti-wear
and extreme pressure additives, friction modifiers, detergents,
antioxidants, detergents either overbased or not, flow point
lowering additives, dispersants, anti-foam additives, thickeners,
polymers enhancing the viscosity index. Preferably, the package of
additives comprises: [0031] from 0.5-30% by weight, preferentially
from 10-25% by weight, of at least one compound (b), a heavy PAO
optionally mixed with a PIB; [0032] from 0.5-15% by weight,
preferentially from 2.75-8.75% by weight of at least one
hydroxylated ester (c).
[0033] According to another object, the invention relates to the
use of a composition according to the invention as a lubricant for
a four-stroke engine. According to another object, the invention
relates to the use of at least one ester of formula R(OH).sub.m
(COOR'(OH).sub.p).sub.n wherein m is an integer from 0 to 8,
preferably from 1 to 4, n is an integer from 1 to 8, preferably
from 1 to 4 and p is an integer from 0 to 8, preferably from 1 to
4, and wherein the sum p+m is strictly greater than zero, R and R'
represent independently of each other a saturated or unsaturated,
linear or branched hydrocarbon group, optionally substituted with
one or more aromatic groups, and including from 1 to 30 carbon
atoms, and its borated derivatives, as a friction modifying agent
for the preparation of a lubricant composition for a four-stroke
engine with a sulfated ash content less than or equal to 0.5% as
measured according to the ASTM D874 standard, a phosphorus content
less or equal to 500 ppm as measured according to ASTM D5185, and a
sulfur content less than or equal to 0.2% as measured according to
the ASTM D5185 standard.
DETAILED DESCRIPTION
[0034] The lubricating composition for a four-stroke engine
according to the invention has a sulfated ash content less than or
equal to 0.5% as measured according to the ASTM D874 standard, a
phosphorus content less than or equal to 500 ppm as measured
according to ASTM D5185, and a sulfur content less than 0.2% as
measured according to the ASTM D5185 standard. Preferably, the
compositions according to the present invention are of the ACEA C4
preferentially ACEA-C1 type, according to the specifications
established by the European Automobile Manufacturers' Association
for gasoline and diesel engine oils for lightweight vehicles.
[0035] The Table below groups together the sulfur, phosphorus,
sulfated ash contents, and the performances in terms of fuel
savings required by these specifications.
TABLE-US-00001 ACEA- ACEA- ACEA- ACEA- C1 C2 C3 C4 Maximum sulfated
ash 0.5% 0.8% 0.8% 0.5% content in % (ASTM D874) Maximum sulfur
content 0.2% 0.32% 0.3% 0.2% in % (ASTM D4294) Maximum phosphorus
500 ppm 900 ppm 900 ppm 500 ppm content (ASTM D5185) Minimum fuel
savings 2.5% 2.5% 1% 1% (measured on a M111FE, CEC L54-T-96 engine
test)
According to an embodiment, the compositions according to the
present invention have a sulfated ash content less than or equal to
0.30%, preferentially less than or equal to 0.25% and a phosphorus
content less than or equal to 300 ppm, preferentially less than or
equal 200 ppm.
[0036] 1) Base Oils or Mixture of Base Oils (a)
[0037] The lubricating compositions according to the present
invention comprise one or more base oils, generally amounting to at
least 50% by weight of the lubricating compositions, generally
larger than 70% and which may range right up to 90% and more.
[0038] The base oil(s) used in the compositions according to the
present invention may be oils of mineral origin or synthetic oils
of Groups I-V according to classes defined in the API
classification (or their equivalents according to the ATIEL
classification) as summarized below, either alone or in a
mixture.
TABLE-US-00002 Saturated Sulfur ingredient content content
Viscosity index Group I: Mineral oils <90% >0.03% 80 .ltoreq.
VI < 120 Group II: hydrocracked .gtoreq.90% .ltoreq.0.03% 80
.ltoreq. VI < 120 oils Group III: hydrocracked .gtoreq.90%
.ltoreq.0.03% .gtoreq.120 or hydro-isomerized oils Group IV PAOs:
Polyalphaolefins Group V Esters and other bases not included in the
bases of Groups I-IV
These oils may be oils of vegetable, animal or mineral origin.
Mineral base oils according to the invention include all types of
bases obtained by atmospheric and in vacuo distillation of crude
petroleum, followed by refining operations such as extraction by a
solvent, deasphalting, dewaxing with a solvent, hydrotreating,
hydrocracking and hydro-isomerization, hydrofinishing.
[0039] The base oils of the compositions according to the present
invention may also be synthetic oils, such as certain esters of
carboxylic acids and alcohols, or polyalphaolefins. The
polyalphaolefins, used as base oils, and which are distinguished
from heavy polyalphaolefins (b) also present in the compositions
according to the present invention, are for example obtained from
monomers having 4 to 32 carbon atoms (for example octene, decene)
and a viscosity at 100.degree. C. comprised between 1.5 and 15 cSt.
Their weight average molecular weight is typically comprised
between 250 and 3,000.
[0040] Mixtures of synthetic and mineral oils may also be used.
There is no limitation to the use of such and such base oil for
producing the compositions according to the present invention, if
not that their amount and their nature should only be adjusted so
as to obtain compositions having a sulfur content less than 0.2% as
measured according to the ASTM D5185 standard, a viscosity grade
and values of viscosity index or VI compatible with a use as a
four-stroke engine oil. Preferably, the compositions according to
the present invention have a kinematic viscosity at 100.degree. C.
comprised between 5.6 and 16.3 cSt as measured by the ASTM D445
standard, (grades SAE 20, 30 and 40), preferentially comprised
between 9.3 and 12.5 cSt (grade 30). According to a particularly
preferred embodiment, the compositions according to the present
invention are of grade 5W30 according to the SAEJ300
classification. The compositions according to the present invention
also preferably have a viscosity index VI larger than 130,
preferentially larger than 150, preferentially larger than 160.
[0041] The main effect on the sulfur content of the lubricants is
obtained by acting on the sulfur content of the base oils used:
this is why base oils having a sulfur content less than 0.3%, for
example mineral oils of Group III, and synthetic sulfur-free bases,
preferentially of Group IV, or a mixture thereof, may be used
advantageously. Thus, the compositions according to the present
invention may contain at lest 70% of base oil, typically at least
60% by weight of one or more base oils of Group III, and at least
10% by weight of one or more base oils of Group IV.
[0042] 2) The Compounds (b): "Heavy" Polyalphaolefins (PAOs) or
Polyisobutenes (PIBs)
[0043] The compounds (b) of the "heavy" polyalpha olefin (PAO) type
or polyalpha olefins "with viscosity" entering the composition
according to the invention are selected from PAOs with a kinematic
viscosity at 100.degree. C. measured according to ASTM D445,
comprised between 75 and 3,000 cSt, preferentially comprised
between 150 and 1,500, preferentially between 300 and 1,200 cSt.
Their number average molecular weight Mn is preferentially larger
than 2,500, typically comprised between 3,000 and 20,000,
preferentially between 3,000 and 10,000, preferentially between
3,000 and 7,000. Their weight average molecular weight Mw is
typically of the order of approximately 4,000 to 50,000, and their
polydispersity index Mw/Mn is of the order of 1.1 to 5 and
more.
[0044] These polyalphaolefins are for example obtained from
monomers such as octene, decene, dodecene, tetradecene, hexadecene,
etc., either alone or mixed with other olefins. They may be used
alone or mixed in compositions according to the invention.
[0045] The compounds (b) of the polyisobutene (PIB) type entering
the composition according to the invention are liquid polymeric
compounds soluble in oil. Their weight molecular weight Mw is
typically larger than 800, typically comprised between 800 and
8,000, usually between 1,500 and 7,000. Their kinematic viscosity
at 100.degree. C. is preferentially comprised between 1,000 and
6,000 cSt (ASTM D445). Typically, the PIBs according to the present
invention have a weight average molecular weight comprised between
2,000 and 5,000 and a kinematic viscosity at 100.degree. C.
comprised between 3,000 and 4,500 cSt.
[0046] The composition may comprise at least one compound selected
from the group of heavy PAOs described above, optionally mixed with
at least one compound selected from the group of polymeric
compounds of the PIB type described above. These compounds (b),
either alone or in a mixture, are totally or partially substituted
for VI-enhancing polymer generating deposits usually present in
engine lubricants formulated with conventional bases. They
therefore allow the detergent content to be lowered. However, fuel
eco performances are a little degraded, because of their bad cold
behavior.
[0047] 3) Hydroxylated Esters (c)
[0048] The composition further comprises at least one ester of
formula R(OH).sub.m (COOR'(OH).sub.p).sub.n wherein m is an integer
from 0 to 8, preferably from 1 to 4, n is an integer from 1 to 8,
preferably from 1 to 4, and p is an integer from 0 to 8, preferably
from 1 to 4 and wherein the sum p+m is strictly greater than zero,
R and R' represent independently of each other a saturated or
unsaturated, linear or branched hydrocarbon group, optionally
substituted with one or more aromatic groups and including from 1
to 30 carbon atoms, and its borated derivatives. According to a
preferred embodiment, the ester (c) has at least one free hydroxyl
OH group belonging to the group R, said OH group being located in
the alpha, beta or gamma position with respect to the carbon of the
CO function of an ester function on which the group R is bound,
and/or contains at least one free hydroxyl OH group belonging to
the group R', said OH group being located in the beta, gamma or
delta position with respect to the oxygen of the COO group of an
ester function on which the group R' is bound.
[0049] Preferably R' represents a C.sub.1-C.sub.10, preferably
C.sub.2-C.sub.6 group. Preferably R represents a C.sub.8-C.sub.25,
preferably C.sub.12-C.sub.18 group. According to one embodiment, p
is strictly greater than zero when the group R of the ester (c)
represents a C.sub.8-C.sub.25, preferably C.sub.12-C.sub.18 group.
According to another embodiment, n is an integer comprised between
1 and 4 when the group R of the ester (c) represents a
C.sub.1-C.sub.5, preferentially C.sub.1-C.sub.3 group.
[0050] The hydroxylated esters (c) may be selected from monoesters
or diesters obtained from glycerol such as glycerol mono-oleate,
glycerol stearate or isostearate and their borated derivatives. The
hydroxylated esters (c) may also be selected from citrates,
tartrates, malates, lactates, mandelates, glycolates,
hydroxypropionates, hydroxyglutarates or their borated
derivatives.
[0051] Surprisingly, the Applicant has shown that by using the
compounds (c), in combination with the compounds (b), it was
possible to formulate from conventional bases, engine lubricants
with good fuel eco performances and good detergency properties,
even if the detergent content remains moderate. Fuel eco, low saps
engine lubricants retaining good detergency properties are thereby
obtained. The compositions according to the invention may for
example comprise from 0.1 to 6%, preferentially from 2 to 4% of at
least one compound (b) and from 0.1 to 2.5%, preferentially from
0.5 to 1.5% of at least one compound (c). The esters of formula
R(OH).sub.m (COOR'(OH).sub.p), according to the invention are
prepared according to methods known to one skilled in the art,
notably by reacting a carboxylic acid of formula R(OH).sub.m
(COOH).sub.n with an alcohol of formula R'(OH).sub.p, the
substituents R, R' and the indices m, n being as defined above.
[0052] 4) Other Additives
[0053] The compositions according to the invention may further
contain any type of suitable additives for use as four-stroke
engine oil. These additives may be introduced separately and/or
included in additive packages used in the formulations of
commercial lubricants for 4-stroke engines, with performance levels
as defined by the ACEA (European Automobile Manufacturers'
Association) and/or the API (American Petroleum Institute) well
known to one skilled in the art. Thus, the compositions according
to the invention may notably contain in a non-limiting way,
anti-wear and extreme pressure additives, friction modifiers,
antioxidants, detergents either overbased or not, polymers
enhancing the viscosity index, flow point enhancers, dispersants,
anti-foam agents, thickeners . . . .
[0054] The anti-wear and extreme pressure additives protect the
rubbing surfaces by forming a protective film adsorbed on these
surfaces. The most currently used one is zinc dithiophosphate or
DTPZn. Various phosphorus, sulfur, nitrogen, chlorine and boron
compounds are also found in this category. There exists a large
diversity of anti-wear additives, but the category which is the
most used in engine oils is that of the phosphorus-sulfur additives
such as metal alkylthiophosphates, in particular zinc
alkylthiophosphates, and more specifically zinc
dialkyldithiophosphates or DTPZn. The preferred compounds are of
formula Zn((SP(S)(OR1)(OR2))2, wherein R1 and R2 are alkyl groups,
preferentially including from 1 to 18 carbon atoms. DTPZn is
typically present in levels of the order of 0.1-2% by weight in the
engine oils.
[0055] Amine phosphates are also anti-wear additives currently
used. However, phosphorus provided by these additives, acts as a
poison for catalytic systems of automobiles, and they also provide
ashes. These effects may be minimized by partly replacing them with
additives not providing phosphorus, such as for example
polysulfides, notably sulfur-containing olefins.
[0056] In lubricating compositions, anti-wear and extreme pressure
additives of the nitrogen- and sulfur-containing type such as for
example metal dithiocarbamates, in particular molybdenum
dithiocarbamate, which also are generators of ashes, are also
usually encountered. Glycerol esters of are also anti-wear
additives. For example, mono-, di- and tri-oleates, monopalmitates
and monomyristates may be mentioned. The anti-wear and extreme
pressure additives are present in the compositions for engine
lubricants in levels comprised between 0.01 and 6%, preferentially
comprised between 0.01 and 4%.
[0057] In the compositions according to the invention, by the
presence of hydroxylated esters or polyalcohol esters (c) it is
possible to limit the amounts of sulfur-containing,
phosphorus/sulfur-containing, nitrogen-containing, and
sulfur-containing additives and of phosphates, so as to achieve a
low content of sulfated ash, sulfur and phosphorus, for example
compatible with the ACEA-C and ACEA-C2 specifications, while
retaining performances compatible with a use as a four-stroke
engine oil. The lubricating compositions according to the present
invention may contain DTPZn, and/or other anti-wear and extreme
pressure additives, in amounts compatible with an overall sulfated
ash content less than 0.5% as measured according to the ASTM D874,
a phosphorus content less than 500 ppm as measured according to
ASTM D5185, and a sulfur content less than 0.2% as measured
according to ASTM D5185 standard. They may contain a DTPZn content
less than or equal to 1% by weight, preferably less than or equal
to 0.5%. They may also be free (0% by weight) of additives
providing phosphorus, for example amine phosphate.
[0058] The friction modifiers encountered in lubricating
compositions for a four-stroke engine may be compounds providing
metal elements or else ashless compounds. Solid compounds are also
found, such as molybdenum sulfide, graphite or PTFE. The metal
compounds for example are complexes of transition metals such as
Mo, Sb, Sn, Fe, Cu, Zn, the ligands of which may be hydrocarbon
compounds containing oxygen, nitrogen, sulfur or phosphorus atoms.
In particular, molybdenum-containing compounds may be particularly
effective, such as for example molybdenum dithiocarbamates,
dithiophosphates.
[0059] The ashless friction modifiers may for example be fatty
alcohols, fatty acids, esters, fatty amines. The friction modifying
additives are generally present in levels comprised between 0.01
and 5%, preferentially 0.01 and 1.5% in the engine lubricants.
[0060] In the compositions according to the invention, by the
presence of hydroxylated esters or polyalcohol esters (c) it is
possible to limit the amount of friction modifiers, providers of
sulfated ashes, phosphorus and sulfur, so as to reach a low content
of sulfated ash, sulfur and phosphorus, for example compatible with
the ACEA-C1 and ACEA-C4 specifications, while retaining
performances compatible with use as a four-stroke engine oil,
notably fuel eco or fuel saving properties, so as to be included in
the ACEA-C1 specification. The compositions according to the
present invention may be free of friction modifiers providing
ashes, for example molybdenum friction modifiers. The lubricating
compositions according to the present invention may however contain
any friction modifying additive types, in amounts compatible with
an overall content of sulfated ashes less than or equal to 0.5% as
measured according to the ASTM D874 standard, a phosphorus content
less than or equal to 500 ppm as measured according to ASTM D5185,
and a sulfur content less than or equal to 0.2% as measured
according to the ASTM D5185 standard.
[0061] The antioxidants delay the degradation of oils in use, a
degradation which may be expressed by the formation of deposits,
the presence of sludges, or an increase in the viscosity of the
oil. They act as radical inhibitors or hydroperoxide-destroying
agents. Aminated antioxidants of the phenolic type are found among
the antioxidants currently used. Some of these additives, for
example the phosphorus-sulfur additives, may be generators of
ashes.
[0062] Phenolic antioxidants may be ashless, or else be in the form
of neutral or basic metal salts. Typically, these are compounds
containing a sterically hindered hydroxyl group, for example when 2
hydroxyl groups are in the ortho or para position with respect to
each other, or when the phenol is substituted with an alkyl group
including at last 6 carbon atoms. The aminated compounds are
another class of antioxidants which may be used, possibly in
combination with phenolic compounds. Typical examples are the
aromatic amines, of formula R.sub.8R.sub.9R.sub.10N, wherein
R.sub.8 is an aliphatic group or an optionally substituted aromatic
group, R.sub.9 is an optionally substituted aromatic group,
R.sub.10 is hydrogen, or an alkyl or aryl group or a group of
formula R.sub.11S(O).sub.xR.sub.12, wherein R.sub.11 is an
alkylene, alkenylene, or aralkylene group, and x is equal to 0, 1
or 2.
[0063] Sulfurized alkylphenols or their alkaline and earth alkaline
salts are also used as antioxidants. Another class of antioxidants
is that of the copper compounds soluble in oil, for example copper
thio- or dithio-phosphates, copper salts of carboxylic acids,
copper dithiocarbamates, sulfonates, phenates, acetylacetonates.
Copper(I) and (II) salts of succinic acid or anhydride are used.
These compounds, either alone or in a mixture, are typically
present in the lubricating compositions for a 4-stroke engine in
amounts comprised between 0.1 and 5% by weight. The lubricating
compositions according to the present invention may contain all
types of antioxidant additives known to one skilled in the art, in
amounts compatible with an overall content of sulfated ashes less
than or equal to 0.5% as measured according to the ASTM D874
standard, a phosphorus content less than or equal to 500 ppm, as
measured according to ASTM D5185, and a sulfur content less than or
equal to 0.2% as measured according to the ASTM D5185 standard.
Ashless antioxidants will be preferred.
[0064] The detergents reduce the formation of deposits at the
surface of the metal parts by dissolving secondary oxidation and
combustion products. The detergents used in the lubricating
compositions according to the present invention are well known to
one skilled in the art. The detergents commonly used in the
formulation of lubricating compositions are typically anionic
compound including a long lipophilic hydrocarbon chain and a
hydrophilic head. The associated cation is typically a metal cation
of an alkaline or earth alkaline metal.
[0065] The detergents are preferentially selected from alkaline and
earth alkaline metal salts of carboxylic acids, sulfonates,
salicylates, naphthenates, as well as phenate salts. The earth
alkaline and alkaline metals are preferentially calcium, magnesium,
sodium or barium. These metal salts may contain the metal in an
approximately stoichiometric amount or else in excess (in an amount
above the stoichiometric amount). In the latter case, one is
dealing with so-called overbased detergents.
[0066] The excess metal providing the overbased character to the
detergents exists as metal salts insoluble in oil, for example a
carbonate, hydroxide, oxalate, acetate, glutamate, preferentially a
carbonate. In a same overbased detergent, the metals of these
insoluble salts may be the same of those of the detergents soluble
in oil or else be different. They are preferentially selected from
calcium, magnesium, sodium or barium.
[0067] The overbased detergents thus appear as micelles consisting
of insoluble metal salts held in suspension in the lubricating
composition by detergents as soluble metal salts in oil. These
micelles may contain one or more types of insoluble metal salts
stabilized by one or more detergent types. The overbased detergents
including a single type of detergent-soluble metal salts will
generally be named from the nature of the hydrophobic chain of the
latter detergent. Thus, they will be said to be of the phenate,
salicylate, sulfonate, naphthenate type depending on whether this
detergent is a salicylate, sulfonate or naphthenate,
respectively.
[0068] The overbased detergent will be said to be of the mixed type
if the micelles comprise several types of detergents, different
from each other by the nature of their hydrophobic chain. The
lubricating compositions according to the present invention may
contain all types of detergents known to one skilled in the art,
either neutral or else overbased or else strongly overbased.
[0069] The more or less overbased character of the detergents is
characterized by the BN (base number), measured according to the
ASTM D2896 standard, and expressed in mg of KOH per gram. Neutral
overbased detergents have a BN comprised between about 0 and 80.
The overbased detergents themselves have BN values typically of the
order of 150 and more, or even 250 or 450 or more. The BN of the
lubricating composition containing the detergents is measured
according to the ASTM D2896 standard and is expressed in mg of KOH
per gram of lubricant.
[0070] It is generally desirable to include in the lubricating
compositions for engines, at least one portion of detergents in an
overbased form, so as to allow neutralization of certain acid
impurities stemming from the combustion and found in the oil. This
being the case, these compounds contain metal salts which generate
ashes, and the formulation of lubricants with low ash content
according to the present invention imposes, while maintaining good
detergency properties, adjustment of the amount of notably
overbased detergents. Thus, the lubricating compositions according
to the present invention may contain any type of detergents known
to one skilled in the art, either neutral or else overbased, or
else strongly overbased, in amounts compatible with an overall
content of sulfated ashes less than or equal to 0.5% as measured
according to the ASTM D2896 standard. Preferentially, the amounts
of overbased detergents included in the lubricating compositions
according to the invention, are adjusted so that the BN of said
compositions, as measured according to the ASTM D2896 standard, is
less than or equal to of 8 mg of KOH per gram of lubricant,
preferentially less than or equal to 6.5, preferentially comprised
between 3 and 6.
[0071] With the viscosity-enhancing polymers, good cold strength
may be guaranteed as well as minimum viscosity at high
temperatures, notably for formulating multigrade oils. By
introducing these compounds into the lubricating compositions,
viscosity index (VI) values may be attained which give them good
fuel eco or fuel-saving properties. Thus, the lubricating
compositions according to the invention have preferably VI values,
as measured according to ASTM D2270, larger than or equal to 130,
preferentially larger than 150, preferentially larger than 160.
[0072] For example, among these compounds, mention may be made of
polymeric esters, olefin copolymers (OCPs), homopolymers or
copolymers of styrene, butadiene or isoprene, polymethacrylates
(PMAs). They are conventionally present at levels of the order of 0
to 40.degree. A), preferentially from 0.01 to 15% by weight, in the
lubricating compositions for a four-stroke engine. These compounds
however have the drawback of forming deposits and their presence in
the formulations, notably in fuel eco formulations, leads one
skilled in the art to increasing the detergent content in the
lubricants, which generates ashes and with which both low saps and
fuel eco specifications of the ACEA Cl or ACEA C2 type cannot be
met. In the lubricants according to the present invention, the
presence of heavy PAOs (b) in an optional mixture with a PIB (b),
as a total or partial replacement of VI-enhancing polymers, and in
combination with the hydroxylated esters (c), allows the detergent
treatment levels to be reduced, and therefore a low ash content may
be achieved. Low sap engine lubricants are thereby obtained with
fuel-saving properties and non-degraded detergency
performances.
[0073] The lubricating compositions according to the present
invention may contain of the order of 0.0 to 10% by weight of
VI-enhancing polymers. Preferably, the compositions according to
the invention contain at most 3% by weight of VI-enhancing polymers
which generate deposits, for example selected from polymeric
esters, olefin copolymers (OCPs), homopolymers or copolymers of
styrene, butadiene or isoprene, polymethacrylates (PMAs),
preferentially at most 2.5% by weight, or are free of them.
[0074] Flow point lowering additives enhance the cold behavior of
the oils, by slowing down the formation of paraffin crystals. For
example, these are alkyl polymethacrylates, polyacrylates,
polyarylamides, polyalkylphenols, polyalkylnaphthalenes, alkylated
polystyrene . . . . The dispersants such as for example
succinimides, PIB (polyisobutene) succinimides, Mannich bases
ensure that the insoluble solid contaminants formed by the
secondary oxidation products which are formed when the engine oil
is being used, are held in suspension and evacuated.
[0075] In order to prepare the lubricating compositions according
to the invention, the compound (b), heavy PAOs and/or PIB,
hydroxylated ester(s) (c) may be introduced as individual
compounds. All or part of the additives may be a part of a
concentrate or package of additives which will be diluted in the
base oil or in the mixture of base oils (a). Thus, some additives
may be introduced via the package and other ones individually. The
VI-enhancing polymers may in particular be added independently of
the package. The object of the present invention is also such
preparation methods, in particular a method wherein the package of
additives is diluted so as to amount to 10-30%, preferentially
15-20% by weight of the lubricating composition, and wherein the
VI-enhancing polymer amounts to 0-3% of the lubricating
composition.
[0076] The object of the present invention is also packages of
additives for a four-stroke engine lubricant with a sulfated ash
content less than or equal to 0.5% as measured according to the
ASTM D874 standard, a phosphorus content is less than or equal to
500 ppm as measured to ASTM D5185, and a sulfur content is less
than or equal to 0.2% as measured according to the ASTM D5185
standard, which comprise: [0077] at least one compound (b), a heavy
PAO optionally mixed with a PIB [0078] at one hydroxylated ester
(c) [0079] optionally, anti-wear and extreme pressure additives,
friction modifiers, detergents, antioxidants, detergents either
overbased or not, flow point lowering additives, dispersants,
anti-foam additives, thickeners, polymers enhancing the viscosity
index.
[0080] Preferentially, the packages of additives according to the
present invention comprise: [0081] from 0.5 to 30% by weight,
preferentially from 10 to 25% by weight, of at least one compound
(b), a heavy PAO optionally mixed with a PIB [0082] from 0.5 to 15%
by weight, preferentially from 2.75 to 8.75% by weight of at least
one hydroxylated ester (c).
[0083] Another object of the present invention relates to the use
of lubricating compositions as described above, as a lubricant for
four-stroke either diesel or gasoline engines, preferentially for
lightweight vehicle engines. Finally, the present invention relates
to the use of hydroxylated esters (c) as described above, as
friction modifiers with which lubricating compositions for
four-stroke engines may be formulated with a sulfated ash content
less than or equal to 0.5%, as measured according to the ASTM D874
standard, a phosphorus content less than or equal to 500 ppm as
measured according to ASTM D5185, and a sulfur content less than or
equal to 0.2% as measured according to ASTM D5185 standard. Of
course, the present invention is not limited to the described and
illustrated examples and embodiment, but it is open to many
alternatives accessible to one skilled in the art.
Example 1
Improvement of the Detergency Properties by Means of PIBs (b') and
Heavy PAOs (b)
[0084] Description of the Compositions and Preparation
[0085] The compositions are described in Table 1.
[0086] The composition A is a reference composition of 5W30 grade
comprising a VI-enhancing polymer of the OCP type.
[0087] In the compositions B, C and D, a portion of the
VI-enhancing OCP polymer was substituted with PIBs or the heavy
PAO, with respect to reference A.
TABLE-US-00003 TABLE 1 Composition and properties A B C D Base oil
Gr IV, mass % 15.00 14.98 14.48 15.13 Base oil Gr III, 22..84 22.81
22.05 23.04 KV 100.degree. C. = 5 cSt, mass % Base oil Gr III,
40.00 39.95 38.62 40.36 KV 100.degree. C. = 4.3 cSt, mass %
VI-enhancing OCP polymer, 8.70 7.30 6.88 4.00 mass % Heavy PAO,
4.00 KV 100.degree. C. = 1,000 mm.sup.2/s, (Spectrasyn Ultra 1000
marketed by Exxon Mobil), mass % PIB (Indopol H2100, marketed by
1.50 Innovene-Ineos Oligomers), mass % PIB (Indopol H100, marketed
by 4.50 Innovene-Ineos Oligomers), mass % Phosphorus, ppm, ASTM
D5185 500 500 500 500 Sulfur, ppm, ASTM D5185 1800 1800 1800 1800
Sulfated ashes, mass % 0.5 0.5 0,.5 0.5 TBN (mg KOH/g) ASTM D2896
4.6 4.6 4.6 4.6 KV 100 mm.sup.2/s, ASTM D445 12 11.94 11.97
[0088] In order to investigate the influence of substituting for
the VI-enhancing OCP polymer, heavy PAOs and PIBs (compounds b and
b' according to the invention, respectively), two laboratory
detergency tests were carried out on oils A, B, C, and D.
[0089] MCT Microcoking Test
[0090] MCT (Micro Coking Test) is a test for evaluating the
deposit-forming tendency on a hot surface (coking).
[0091] The test conditions are the following:
[0092] MCT (according to the GFC Lu-27-A-03 v.2 standard) [0093] 60
.mu.L of oil (+10 ppm of anti-foaming agent) [0094] duration: 90
min [0095] plate tilted by 1-2% including a bucket [0096] a
temperature gradient from 230 to 280.degree. C. [0097] scoring of
the varnishes of the plate: so-called "division of squares (/10)"
method 2.
[0098] ECBT Test
[0099] ECBT (Elf Coking Bench Test) is a test of heat strength on a
coking bench. It simulates an engine piston brought to a high
temperature which is spread with oil projections from a crankcase.
The lubricant arrives on a very hot surface, is altered and gives
rise to deposits. With this test, it is possible to approach the
nature of the deposits formed on the upper portions of the piston
(crown, first groove and piston bottom) as well as obtain an
estimation of the resistance of the oil to alteration. As compared
with MCT, this test is dynamic. A description of this test may be
consulted in the Proceedings of the Motorship Marine Propulsion
Conference 2000, Amsterdam, March 29-30, "The relevance of
laboratory tests in simulating field performance", by J P.
Roman.
[0100] ECBT Test Conditions
[0101] About 400 g of oil.
[0102] Duration: 1 hr sweep at different temperatures
[0103] Temperatures: 290, 300 and 310.degree. C.
[0104] Aluminum beaker
[0105] No final sweep during cooling
[0106] Scoring of the sweeped area of the aluminum beaker
(/100)
[0107] F9Q Detergency Engine Test
Detergency properties are also evaluated by an F9Q engine test,
under the following conditions: [0108] 1.9 liter common rail diesel
engine [0109] duration 96 hours [0110] 4,000 rpm at full load
[0111] scoring of piston fouling (varnish/carbon/global)
[0112] Table 2 gives the results of the detergency tests obtained
for oils A, B, C and D. It is seen that at a set detergent content
(a set TBN), detergency performances of oils B, C, D where PIBs or
heavy PAO are partially substituted for the OCP polymer, are better
than those of the reference oil A, which only contains OCP.
TABLE-US-00004 TABLE 2 detergency tests Heavy REF PIB PIB PAO A B C
D Laboratory detergency tests MCT (av. merit/10) Score 2 8.0 8.5
8.5 8.6 ECBT, 1 hr@290.degree. C. (score/100) 34.3 50.4 38 36.6
ECBT, 1 hr@300.degree. C. 19.5 32.4 23.9 22.5 ECBT, 1
hr@310.degree. C. 16 22.5 22.9 16.9 F9Q detergency engine test
Carbon score/10 8.2 8.4 Varnish score/10 4.9 5.3 Overall score/100
59.4 62.2
Example 2
Improvement of Fuel Eco Properties by Means of FM Triethyl Citrate
(c) in the Presence of PIB (b)
[0113] Description of the Compositions and Preparation
[0114] Composition A' is a reference composition with a very low
ash, sulfur and phosphorus content, of 5W30 grade, with a
VI-enhancing polymer different from that of reference A. The mass
composition of the A' oil as well as its properties, are given in
Table 2. The composition B' was prepared by adding 1% by mass of
triethyl citrate to the composition A'.
[0115] Fuel Eco Properties
[0116] The fuel eco properties of oils A' and B' were measured by a
laboratory friction test Cameron Plint. This laboratory test is
correlated with the M111FE (CEC L54-T-96 standard) engine tests.
The test bench consists of a plane cylinder tribometer immersed in
the oil to be tested. A variable normal force is applied on the
heated plane and the resulting friction force is measured. By
comparing the results with those obtained for the reference oils
from the Mill FE (CEC L54-T-96 standard) engine test, it is
possible to calculate the fuel savings made with the tested
oil.
[0117] The results reported in Table 3 below show the improvement
in fuel eco properties induced by addition of triethyl citrate.
TABLE-US-00005 TABLE 3 A' B' Gr III, KV 100.degree. C. = 4 cSt,
mass % 50.00 49.50 Gr III, KV 100.degree. C. = 6 cSt, mass % 20.00
19.80 Base oil Gr IV, PAO KV 100.degree. C. = 4 cSt, 10.00 9.90
mass % VI-enhancing polymer (hydrogenated 6.50 6.43
isoprene-styrene), mass % Triethyl citrate (a), mass % -- 0.99 PIB
(b), mass % 2.00 1.98 Phosphorus, ppm 183 181 Sulfur, mass % 0.053
0.052 Sulfated ashes, mass % 0.23 0.23 TBN (mg KOH/g) ASTM D2896
3.43 3.40 TBN (mg KOH/g) ASTM D4739 2.53 2.50 KV 100 mm.sup.2/s
11.89 11.89 Cameron Plint (fuel savings %) 1.75 2.02
Example 3
Improvement of Fuel Eco Properties and Detergency by the Heavy PAO
(b)+Triethyl Citrate (c) Combination and by the Heavy PAO
(b)+Glycerol Monoisostearate (c) Combination
[0118] Description of the Compositions and Preparation
[0119] Composition E is a reference composition of grade 5W30
comprising a VI-enhancing OCP type polymer, and a package of
additives comprising dispersants, detergents (weakly and strongly
overbased calcium sulfonates and phenates), DTPZn, a friction
modifier, aminated and phenolic antioxidants, an anti-foam
additive, a flow point lowering agent.
[0120] In compositions F, G and H, as compared with reference E, a
portion of the VI-enhancing OCP polymer is substituted with a heavy
PAO, with a kinematic viscosity at 100.degree. C. of 1,000
mm.sup.2/s, marketed by Exxon Mobil under the name of SpectraSyn
Ultra 1000.
[0121] Compositions G and H are compositions according to the
invention, wherein the VI-enhancing polymer is partly substituted
with this same heavy PAO (compound (b)) and further comprising 1%
by weight of a compound (c), triethyl citrate and glycerol
monoisostearate, respectively.
[0122] The compositions (in mass %) and the physicochemical
properties of compositions E, F, G, H, are given in Table 4.
[0123] "Fuel Eco" or Fuel-Saving Properties
[0124] "Fuel eco" or fuel-saving properties of the compositions E,
F, G, H were evaluated by a M111FE engine test and by a Cameron
Plint laboratory test.
[0125] The detergency properties were evaluated by the ECBT test
conducted at 280.degree. C.
[0126] The results are grouped in Table 5.
[0127] Conditions of the Fuel Eco Engine Test M111FE (CEC L54-T-96
Standard)
[0128] 2 L gasoline engine of 100 kW
[0129] Cycles which represent haulage with strong urban character:
[0130] engine speed between 750 and 3,070 rpm [0131] power between
0 and 49 KW [0132] oil temperature between 20 and 75.degree. C.
[0133] Measured fuel savings as compared with a reference oil of
grade 15W40 (RL191).
[0134] Conditions of the Cameron Plint Fuel Eco Laboratory Friction
Test
[0135] This laboratory test is correlated with M111FE (CEC L54-T-96
standard) engine tests. The test bench consists of a plane cylinder
tribometer, immersed in the oil to be tested. A variable normal
force is applied on the heated plane and the resulting friction
force is measured. By comparing the results with those obtained for
the reference oils from the M111 FE (CEC L54-T-96 standard) engine
test, it is possible to calculate the fuel savings made with the
tested oil.
TABLE-US-00006 TABLE 4 compositions (in mass %) and physicochemical
properties Base oil: E (Ref) F G H Gr IV PAO, KV 100.degree. C. = 6
cSt 15.20% 15.20% 15.05% 15.05% Gr III, KV 100.degree. C. = 6 cSt
14.90% 14.80% 14.65% 14.65% Gr III KV 100.degree. C. = 4 cSt 50.80%
50.80% 50.30% 50.30% Total base oil 80.90% 80.80% 80.00% 80.00% OCP
polymer 5.10% 2.20% 2.20% 2.20% Heavy PAOs, KV at 100.degree. C.
1000 mm2/s, 3.00% 3.00% 3.00% Spectrasyn 1000 Glycerol
monoisostearate 1.00% Triethyl citrate 1.00% Additive package
comprising: weakly and 13.80% 13.80% 13.80% 13.80% strongly
strongly overbased detergents; aminated and 0.50% 0.50% 0.50% 0.50%
phenolic ashless antioxidants, succinimide dispersant, amine
phosphate anti-wear agent, including, DTPZn Flow point lowering
agent 0.20% 0.20% 0.20% 0.20% Sulfated ashes* 0.50% 0.50% 0.50%
0.50% Phosphorus** (ppm) 509 ppm 509 ppm 500 ppm 500 ppm %
sulfur*** 0.128% 0.128% 0.128% 0.128% TBN mgKOH/g ASTM D2896 5.95
5.95 5.95 5.95 KV at 100.degree. C., in mm.sup.2/s ASTM D445 9.96
9.94 10.04 9.952 KV at 40.degree. C., in mm.sup.2/s ASTM D445 57.65
57.81 57.99 56.64 VI 160 159 161 164 *ASTM D874 measurement, **ASTM
D5185 measurement, ***ASTM D5185 measurement.
TABLE-US-00007 TABLE 5 fuel eco and detergency properties
Compositions E (ref) F G H Detergency ECBT 280.degree. C. 25.90
34.20 36.90 35.30 Fuel Economy FE Cameron Plint 1.97 1.78 2.38 2.04
(fuel savings %) M 111 FE 2.57 1.90 2.19 2.50 (fuel savings %)
[0136] Detergency Results
[0137] By partly substituting OCP with heavy PAO, in composition F,
the formation of deposits may be minimized, therefore detergency
properties may be improved as compared with reference E, with a
constant detergent treatment level. Addition of hydroxylated esters
has no influence and the good detergency performances are
preserved.
[0138] Fuel Eco Results
[0139] Partial substitution of the VI-enhancing OCP type polymer
with a heavy PAO has a positive effect on detergency (transition
from 25.30 to 34.20 in ECBT 280.degree. C.) but a negative effect
on fuel eco properties (transition from 1.97 to 1.78 in the Cameron
Plint test and from 2.57 to 1.90 in the M111FE engine test). By
adding hydroxylated ester in compositions G and H, it is possible
to compensate lowering of the fuel eco property and to even improve
it relatively to the reference.
* * * * *